Medium-Term Cardiac Outcomes in Young People with Multi-system Inflammatory Syndrome: The Era of COVID-19

Multi-system inflammatory syndrome in children (MIS-C) causes widespread inflammation including a pancarditis in the weeks following a COVID infection. As we prepare for further coronavirus surges, understanding the medium-term cardiac impacts of this condition is important for allocating healthcare resources. A retrospective single-center study of 67 consecutive patients with MIS-C was performed evaluating echocardiographic and electrocardiographic (ECG) findings to determine the point of worst cardiac dysfunction during the admission, then at intervals of 6–8 weeks and 6–8 months. Worst cardiac function occurred 6.8 ± 2.4 days after the onset of fever with mean 3D left ventricle (LV) ejection fraction (EF) 50.5 ± 9.8%. A pancarditis was typically present: 46.3% had cardiac impairment; 31.3% had pericardial effusion; 26.8% demonstrated moderate (or worse) valvar regurgitation; and 26.8% had coronary dilatation. Cardiac function normalized in all patients by 6–8 weeks (mean 3D LV EF 61.3 ± 4.4%, p < 0.001 compared to presentation). Coronary dilatation resolved in all but one patient who initially developed large aneurysms at presentation, which persisted 6 months later. ECG changes predominantly featured T-wave changes resolving at follow-up. Adverse events included need for ECMO (n = 2), death as an ECMO-related complication (n = 1), LV thrombus formation (n = 1), and subendocardial infarction (n = 1). MIS-C causes a pancarditis. In the majority, discharge from long-term follow-up can be considered as full cardiac recovery is expected by 8 weeks. The exception includes patients with medium sized aneurysms or greater as these may persist and require on-going surveillance.